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Effect of uniaxial stretching on the tensile impact test for poly(ethylene terephthalate)
Author(s) -
Yokouchi Mitsuru,
Hiromoto Yasuyuki,
Kobayashi Yasuji
Publication year - 1979
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1979.070240904
Subject(s) - materials science , isotropy , composite material , anisotropy , deformation (meteorology) , ultimate tensile strength , poly ethylene , amorphous solid , izod impact strength test , tensile testing , deformation mechanism , ethylene , crystallography , microstructure , optics , biochemistry , chemistry , physics , catalysis
In order to correlate impact strength with the structure of polymeric materials, a tensile impact test was carried out using a uniaxially stretched poly(ethylene terephthalate) (PET) sheet. The structural factors were the draw ratio (λ) and the cut‐out angle (θ) under the conditions of constant impacting speed (10.5 m/sec = 1.8 × 10 4 %/sec) and temperature (20° ± 1°C). The occurrence of structural anisotropy by stretching of isotropic amorphous quench‐rolled PET was classified into three drawing stages: λ = −1.5 or 2.0, −3.5, and over 3.5. This is related to a deformation mechanism of masses with dimensions a few tenths of a μm and their boundaries. The boundaries are not clear until adiabatic deformation (mechanical impact) is applied. The area supporting the mechanical strength was limited to just a small section. Its character was affected by macroscopic deformation only in the direction parallel or near to the stretching direction, since the mechanical properties were not changed for the range of the cut‐out angle θ = 45–90°.